A cylinder is painted in 6 colours - Green, Blue, Yellow, Violet, Red and Orange. Three positions are shown below :
What is the missing colour ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Violet
The cylinder has six coloured parts: two flat ends and four strips round the curved surface. Strips seen side by side in a position are neighbours; the strip that never appears beside a colour is the one opposite it.
The ends and the strips:
Yellow (i) and Orange (ii) are shown as ends, so the ends are Yellow and Orange
The four strips are therefore Green, Blue, Violet and Red
Neighbours and opposites:
Green is beside Blue in (i) and beside Violet in (ii)
So Red is opposite Green, and Blue is opposite Violet
The strip above Red in (iii) is a neighbour of Red, so it is Blue or Violet, never Green
Which of the two: seen from its two ends, the four strips run round in opposite directions. In (i) Green and Blue face you, with Violet and Red behind them; turning the cylinder end for end, so that Orange is on the right as in (iii), brings Violet and Red to the front, Violet at the top and Red at the bottom.
